The so-called electronic crossover is the circuit topology design before the frequency dividing circuit is sent to the amplifying circuit, which is as simple as this.
Electronic crossover is not a new technology, and it is very common to apply to professional audio equipment on stage. Since the signal power is small when the electronic crossover is performed, it is easy to accurately separate the frequencies, and it is possible to divide the frequency according to the characteristics of the speaker unit, and maximize the characteristics of the speaker unit to obtain the most straight and satisfactory listening curve.
What are active and passive car audio electronic crossovers?In order to realistically reproduce various program signals, the speaker is required to have a wide and flat frequency response as possible, and the reproduction frequency range of the speaker must reach 50 to 12500HZ even if the HI-FI is required for the lowest low-frequency response. . In fact, due to the objective limitations of the structure of the field and the manufacturing process, no single speaker can work well in such a wide frequency range. Each type of speaker has its effective frequency range and works well in a narrow range. If the actual operating frequency of the speaker exceeds its effective frequency range, the distortion and directivity of the speaker will be significantly deteriorated. . To this end, people have created speakers for different frequency ranges, such as low frequency speakers, intermediate frequency speakers, high frequency speakers and so on.
In this way, the sound of the frequency range of 20HZ~20KHZ that can be heard by the human ear is separately sent through the low frequency speaker, the intermediate frequency speaker and the high frequency speaker. However, it is not possible to directly connect the two types of speakers in parallel. It is necessary to have a device to do a "frequency allocation work". The frequency divider is created. The function of the frequency divider is to divide the full-band signal of 20~20KHZ into Different frequency bands are redistributed to the corresponding speakers.
When we are installing a car audio set speaker, we often come into contact with a device - the electronic crossover. It is sometimes hidden under the instrument panel and sometimes hidden in the door trim panel. Some friends may be curious, what is the use of this electronic crossover? Is there no electronic crossover? For everyone's questions, combined with the information of all parties, simply introduce you to the electronic crossover!
What is an electronic crossover:
Literally, the electronic crossover means “equipment that distinguishes frequenciesâ€. In fact, the scientific principle is also the same. The weak signal of the audio is divided, then transmitted to the power amplifier, and the audio signal is amplified and finally transmitted to each speaker. .
The role of the electronic crossover:
First, it receives a weak audio signal from the car host, and then distinguishes it (like the human brain), which signal is required for the tweeter, and which signal is required for the woofer, which is differentiated by it, then It is transmitted to the power amplifier, and the amplifier will amplify the signal and transmit it to each part of the speaker. The advantage of this is signal interference, improved dynamic range, and a certain amplification effect. This allows each speaker to better display its sound quality!
Material and shape of the electronic crossover:
The electronic crossover is mainly composed of various transistors, integrated circuits and RC components, and the RC is mostly made of pure copper.
In terms of styling, it is mainly based on square shapes. For example, the Huiwei D630 three-way electronic crossover adopts the traditional square shape.
Of course, there are also more individual styles, such as the Moray Ile three-way electronic crossover, the use of fish bone shape!
Installation of the electronic crossover:
At present, there are two main ways to install an electronic crossover when performing car audio conversion.
1. Installed in the door trim panel. In this way, the space of the door trim panel needs to be sufficient, and it is preferable to have a groove portion.
2. Install the underside of the instrument panel of the car. Pay attention to the line discharge during installation to avoid affecting the internal wire of the car body.
3. Another is to perform a mold installation. However, this type of crossover installation method is more complicated, and generally only suitable for the car installation of the trunk mold.
Car audio is simple. The difference between active and passive is that the frequency division process is called active before or after power amplification, and the frequency division is called active before the power amplifier. . Both active and passive have their own advantages. Sound also has its own advantages and disadvantages. It is necessary to make choices according to your own needs, rather than listening to others to take the initiative to play active. Here are the advantages and disadvantages of these two kinds of crossover.
Disadvantages of passive crossover:
The signal of the power amplifier is processed by the frequency divider to be sent to the corresponding speaker unit for sound operation. Nearly 20% of the power loss will be on the frequency divider. The nonlinear distortion of the frequency division component will directly affect the sound quality. The inductance lag and the lead phase difference of the capacitor are also difficult to handle. The load of the power amplifier is first the frequency divider and then the speaker. The frequency dividing component directly increases the damping coefficient of the power amplifier, and the transient characteristics are slightly worse, which also makes the power control of the power amplifier worse. The load of the frequency divider is a horn, the impedance of the horn is changed, and the operation of the frequency divider requires a constant resistance, and the frequency dividing point is prone to drift. Therefore, it is necessary to adjust the impedance state or phase of the horn to adjust the auxiliary circuit. In addition, the insertion loss and the sound dyeing are added, and the sensitivity adjustment between the units is realized by the resistance attenuation. Even the best resistance is unsanitary for the sound quality. . The frequency of the passive crossover is mostly fixed, and it can't be adjusted casually. For the car audio tuning, it is not flexible enough to adjust the frequency. (FOCAL's new Utopia can adjust the crossover point and slope),
Advantages of passive crossover:
Simple to make (if you know a certain principle), the cost is low, the quality of the power amplifier is not high, and the main requirement is that there are not many requirements for the power amplifier. The power amplifier can also be promoted (not necessarily pushed). Generally, the power amplifier can be used. Push two crossover or three-way speakers. Simple debugging requires only a slight adjustment of the sensitivity of the treble (three-way adjustment of the mid-range sensitivity) to get a good balance or good sound. If it is a DIY enthusiast, you can change the crossover point or crossover slope and replace the components to adjust the sound characteristics, which is the biggest charm of using the passive crossover for a long time! ! I also have a soft spot for this advantage. And research has learned several alternative ways of playing. The advantage of this is that the speakers of the same model brand, different designers or manufacturers will have different sounds after use, which is largely the contribution of passive frequency division, and also related to the material of the cabinet and the cabinet. It has nothing to do with the theme. Because the passive crossover can control the final sound of the speaker, easy to use and many other advantages, there are still many manufacturers who continue to use tens of thousands of thousands or even hundreds of thousands of household speakers, but the materials and design are adequate. Work hard. For example, a manufacturer's 12DB crossover plus an auxiliary adjustment circuit has a maximum of thirteen or four components per channel, but the designer uses more than twenty components, which is the result of adding new technology and adjusting the circuit. .
Disadvantages of active crossover:
Need to use multi-channel power amplifier drive, each speaker needs a separate channel drive, the cost is high, you need to purchase an electronic active crossover, which greatly increases the cost, improper debugging will likely burn the tweeter or let the speaker get up early Entering the aging period affects the sound performance, and the debugging is more complicated. If the debugging is not correct, it may not be as good as the balance of the passive sound. Adjusting it requires a deeper theory of electroacoustics, and better tuning experience to control the active crossover.
Advantages of active crossover:
It is said that most of the circuits are divided into capacitors and resistors, and the same components are used for high-pass and low-pass. The phase consistency is good! This means that the phase difference is extremely small. (In this case, a few personal understanding of the phase has a new understanding of the phase, but it is not necessarily correct. Almost many instruments cover the frequency range of high, medium and low, but not complete. Then, if the sound of this instrument is reproduced in balance, the ratio of pitch and overtone is correct, the sound is more realistic, and there is phase. Two or more speakers replay the sound of the instrument. It can be simply understood that the time for each band to sound or reach the human ear is the same, then the restoration of the positioning or shape sound characteristics is more real and natural. The active frequency division is divided at the input end of the power amplifier, and the load is the input end of the power amplifier. The impedance is high and stable, and it is not easy to generate frequency drift. The frequency-divided signal is amplified by the power amplifier and directly drives the speaker with a lot of nonlinear distortion components. The distortion is reduced, and the intermediate insertion loss power transmission is reduced. Compared with the improvement, the transient of the horn is not improved, the analysis of the sound system is improved, and the details are displayed. Clear, but also for changes in the automotive environment can adjust the crossover frequency convergence is more smooth, clear sense of hierarchy, etc. will be apparent from the account of the speaker placement. Each amplifier works in different frequency bands to reduce intermodulation distortion and distortion. Different speaker signal transmissions can use signal lines and speaker lines that are more suitable for a certain frequency band, so that the signal transmission efficiency or sound characteristics are more style. In fact, careful study of active crossover and a lot of gameplay to explore.
However, if the system equipment itself is not good enough to play the active crossover, it is a waste of money. I have seen a lot of people use the speakers that are very cheap and not very good to take the initiative. The sound is not as good as the whole set of audio and the same brand of power amplifier and speaker passive crossover sound is good! If you play this way, you are too superstitious about some practices and ignore the important role of matching in the sound.
The main function of the safety barrier is to restrict the dangerous energy in the safe place from entering the dangerous place, that is, to limit the voltage and current sent to the dangerous place.
1. Due to the tripartite isolation mode, there is no need for system grounding line, which brings great convenience to the design and on-site construction. The requirements for instruments in hazardous areas are greatly reduced, and isolated instruments are not required on site.
2. Since the signal line does not need to be grounded together, the stability and anti-interference ability of the detection and control circuit signal are greatly enhanced, so as to improve the reliability of the whole system.
3. The isolated safety barrier has stronger input signal processing ability and can accept and process thermocouple, thermal resistance, frequency and other signals, which is impossible for Zener safety barrier.
4. The isolated safety barrier [2] can output two mutually isolated signals to be used by two equipment using the same signal source, ensure that the signals of the two equipment do not interfere with each other, and improve the electrical safety insulation performance between the connected equipment.
Isolated Safety Barrier,Output Intrinsic Isolated Safety Barrier,Explosion-Proof Relay Isolated Barrier,Switch Explosion-Proof Relay Barrier
Taizhou Jiabo Instrument Technology Co., Ltd. , https://www.jbcbyq.com